机电工程专业英语总复习资料(机械制造)

Lesson 1The major part of a machine is the mechanical system .And the mechanical system is decomposed into mechanisms ,which can be further decomposed into mechanical components .In this sense ,the mechanical components are the fundamental elements of machinery. On the whole ,mechanical components can be classified as universal and special component .Bolts ,gear ,and chains are the typical example of the universal components ,which can be used extensively in different machines across various industrial sectors .Turbine blades ,crankshaft and aircraft propeller are the examples of the special components ,which are designed for some specific purposes .机器的主要部分是机械系统，机械系统可以分解成机构，机构又可以进一步分解成机械零件。

因此，机械零件是构成机器的基本单元。

总体上来讲，机器零件可以分为通用零件和专用零件两类。

螺栓、齿轮和链条是典型的通用型零件，它们广泛应用在各种工业部门的不同机器上。

涡轮机的叶片、曲轴和飞机的螺旋桨属于专用零件，它们具有一些特殊用途。

Machinery design is either to formulate an engineering plan for the satisfaction of a specified need or to solve an engineering problem.机械设计用以阐明满足某种特殊需要的工程计划或解决具体的工程问题。

Provides an introduction to the design process,problemformulation ,safety factors.提供设计过程、计算公式及相应的安全设计指标。

Reviews the material properties and static and dynamic loading analysis ,including beam ,vibration and impact loading .提供材料特性、静态和动态载荷分析，包括梁、振动和冲击载荷。

Lesson 2A mechanism is the members combination more than two or two connections with the members to realize the regulation motion made up by way of the activity .They are the component of machinery .Activity connections between members that have the relative motion are called the motion pairs .All motion pairs contact with planes are called lower pairs and all motion pairs contact with points or lines are called high pairs.~~~~~~The independent parameter (coordinate number) essential for description or definite mechanism motion is called the free degree of mechanism.机构是两个或两个以上的构件通过活动联接以实现规定运动的构建组合，是机械的组成部分。

两个有相对运动的构件间活动连接称为运动副。

其中凡以面接触的运动副称为低副，凡以点或线接触的运动副称为高副。

~~~~~~~描述或确定机构的运动所必须的独立参变量（坐标数）称为机构自由度。

The motion specific property of mechanism chiefly depends on the relative size between the members ,and the character of motion pairs ,aswell as the mutual disposition method etc.机构的运动特性主要取决于构件的相对大小、运动副的性质以及相互配置方式等。

The plane four-bar linkage ,the plate cam and driven parts ,and the slider-crank mechanism are familiar examples of planar mechanism .平面四连杆机构、平面盘形凸轮、从动件及曲柄滑块机构等都是平面机构的常见例子。

A cam is machine member that drivers a follower through a specified motion .By the proper design of a cam ,any desired motion to a machine member can be obtained .凸轮是一个驱动从动件实现某一具体运动的机械零件。

通过恰当的凸轮结构设计，可以使机器零件获得任何预期运动。

Lesson 3Gears are direct contact bodies ,operating in pairs ,that transmit motion and force from one rotating shaft to another ,or from shaft to slide (rack) ,by means of successively engaging projections called teeth .齿轮副是有相互直接接触的齿轮组成，通常成对使用，在齿轮连续啮合的作用下，齿轮将运动和力从一根转轴传递到另一根转轴上，或者将运动从和力从一根轴传递到滑块（齿条）上。

Standard roller chains are available in single strands or in multiple strands .In the latter type ,two or more chains are joined by common pins that keep the rollers in the separate strands in proper alignment .标准滚子链可以是单排的，也可以是多排的。

如果是多排的，那么两条或者多条链条连接在同一个销轴上，这时要使滚子以一定的排列方式对齐。

Roller chains are assembled from pin links and roller links.A pin link consist of two side plates connected by two pins inserted into holes in the side plates .The pins fit tightly into the holes ,forming what is known as a press fit .A roller link consists of two side plates connected by two press-fitted bushings , on which two hardened steel rollers are free to rotate .When assembled ,the pins are a free fit in the bushings and rotate slightly ,relative to the bushings when the chain goes on and leaves a sprocket .滚子链条是用销轴和滚柱等进行装配而成的，用两个销轴插入两个链板中的孔，可以连接内、外链板，销轴紧紧地插入孔中，形成压紧连接。

滚子由内、外链板和两个压紧套筒组成，硬的钢质滚柱可以自由转动。

装配好后，销轴与套筒之间的配合为自由配合，随着链条在链轮上传动，销轴可相对于套筒作轻微的转动。

Lesson 4Nuts ,bolts ,and screws are undoubtedly the most common means of joining materials .Since they are so widely used ,it is essential that these fasteners attain maximum effectiveness at the lowest possible cost .螺帽、螺栓和螺钉毫无疑问是最通用的紧固件，由于它们应用得如此广泛，因此要求这些紧固件价格低、功效高和成本低是必须的。

Shafts are mounted in bearings and transmit power through such devices as gears ,pulleys,cams and clutches .These devices introduce forces which attempt to bend the shaft ,hence ,the shaft must be rigid enough to prevent overloading of the supporting bearings .轴安装在轴承中，通过齿轮、皮带轮、凸轮和离合器等传递动力。

通过这些零件传递的力可能会使轴发生弯曲变形，因此，轴应该有足够的刚度以防止支承轴承力过大。

Another important aspect of shaft design is the method of directly connecting one shaft to anther .This is accomplished by devices such as rigid and flexible couplings.在轴的设计中，另一个需要重点考虑的是轴与轴之间的连接方法。